Post Fire Stability Hans Gerlich for Winstone Wallboards Ltd

Post Fire Stability

Hans Gerlich

for Winstone Wallboards Ltd

‘Post-Fire’ ‘Stability’

‘Stability’vs

‘Structural Adequacy’

not the same

‘Structural Adequacy’

Ability of a specimen to resist vertical loads, applied

in a standard furnace test

e.g.,30/30/30

Commonly involves lateral forcesnot by test but by design

Designing for Stability

in accordance with

NZBC B1/VM1

During and After fire

Designing for Stability

Of boundary fire walls

FRR based on ‘Time Equivalence’ or ‘S’ rating

based on FLED and constant ventilation conditions FRR rounded (up) in C/AS documents

Post-fire stability required on assumption of

building collapse significantly increased ventilation much lower FRR

High FRR - compartment integrityStability - compartment failure

FRR of Boundary Fire Wall

‘Post-Fire’

Post-Fire

NZBC B1/VM1

‘After the fire until the building is either repaired or

demolished’

??

Post-Fire Stability

Many questions remain, such as;

• What are we trying to achieve?• What elements require post-fire stability?• Are the B1/VM1 provisions workable?• Do we have the FRR right? • One way or two-way?

MBIE Work Group

MEFE Thesis – Daniel JessopFire Performance of a Laterally Loaded LTF Structure

Horizontal furnace testISO 834 standard time-temperature curve

30.5 mins – Run-away deflection in fire-rated wall, furnace shut-off

30.5 minutes Run-away deflection in fire-rated wallfurnace shut-down

C/AS1NZS3604

NZBC Compliance

B1 – Structure C 1-6 Protection from Fire

Thanks for Listening !

In short;

• ‘Stability’ vs ‘Structural Adequacy’• ‘Post-Fire’• B1/VM1 provisions• Required FRRs for Boundary Walls• Testing LTF structure (MEFE Project - Daniel Jessop)